Number of 2's in n-th term of A007651.

Terms

a(0) =0a(1) =0a(2) =1a(3) =1a(4) =2a(5) =2a(6) =3a(7) =2a(8) =3a(9) =4a(10) =8a(11) =10a(12) =14a(13) =18a(14) =24a(15) =28a(16) =41a(17) =56a(18) =69a(19) =91a(20) =123a(21) =164a(22) =221a(23) =286a(24) =366a(25) =494a(26) =636a(27) =832a(28) =1095a(29) =1423